Cloth motion in looms



Fe. 1.8, 1969 E. PFARRWALLER 3,428,095

CLOTH MOTION IN LOOMS Sheet of In ventor:

Erwin Pforrwoller BY G ATTORNEYS Feb. 18, 1969 E. PFARRWALLER CLOTH MOTION IN LOOMS Z of 2 Sheet- Eiled Oct. 17, 1966 a 0G Y t W 1M M m. w m m In ,A w E United States Patent 14,973/ 65 US. Cl. 139-304 6 Claims Int. Cl. D03d 39/22, 49/20, 49/06 ABSTRACT OF THE DISCLOSURE There is disclosed a loom in which the back rest is resiliently supported to apply a substantially constant tension to the warp threads passing over it and in which there are provided means, coupled by a cam-operated linkage to the drive for the reed, to superpose a reciprocating motion on the normal advance of the cloth. In certain embodiments these means comprise the breast-beam of the loom, coupled to the drive for the reed by the camoperated linkage. In other embodiments these means comprise a draw-01f roll for the cloth, and the linkage superposes a reciprocating arcuate oscillation on the advance of the draw-off roll, by axial reciprocation of a worm engaging a worm wheel on the draw-off roll, or via a differential in the drive to the draw-off roll.

The present invention pertains to looms for the weaving of cloth, and more particularly to the mechanism which advances the warp threads and the woven cloth past the location where the shed is formed by the weaving harnesses. The invention provides an improved construction for a loom which stabilizes the position of the ends or limits of the shed lengthwise of the warp threads, and particularly of the end of the shed at the fell, thus ensuring adequate space for passage of the shuttle or shuttles. The end of the shed at the fell will hereinafter be called the front apex of the shed.

In the usual loom construction the cloth moves forward, either continuously or intermittently, passing from the fell at which the weft is beaten up by the reed on to a draw-off roller and thence onto a cloth beam on which it is wound up. This normal forward motion, whether continuous or intermittent, may include, according to the set of the weft and the nature of the weft yarn, a short backward motion at each pick, occurring immediately after beating up and produced by the action of the reed. Additionally, with closely woven fabrics and highly resilient yarns the front apex of the shed may retreat back toward the warp beam after beating up, so much so in some cases as to reduce the length of the shed sufliciently to interfere with safe passage of the shuttle. Likewise there may occur the undesirable result that the warp threads will undergo excessive stress at the heddles by increased friction there when the inclination above the horizontal of the warp threads in the upper half of the shed and the inclination below the horizontal of the warp threads in the lower half of the shed increases, as it does with such retreat of the front apex of the shed. That is, the more the front apex of the shed retreats, the greater will be the friction undergone by the warp threads in passing through the heddles.

The present invention provides a loom having superimposed on this normal cloth motion, i.e. apart from the effect of the beating reed, a controlled momentary forward or backward motion of the cloth or a controlled momentary acceleration or deceleration thereof. For convenience, this added motion will sometimes hereinafter be referred to as a seesaw motion. Thus in accordance with the invention, the cloth may be advanced at increased speed immediately after beating up, so that the variation between the position of the frront apex of the shed upon beating up and the position thereof when the reed is retracted from the fell is wholly or partly suppressed, the front apex being maintained at or nearly at the position which it occupies when the reed is beating up the weft, i.e. in the farthest forward position of the reed. This maximizes the space available for the shuttle between the upper and lower halves of the shed.

According to a further feature of the invention, provision may be made to cause the cloth to move backwardly during beating up. This can be especially advantageous in the weaving of closely-woven cloths.

The cloth movement may according to the invention be such that during the pick, the cloth remains in the forward position of its seesaw motion. The spacing between the threads in the upper and lower halves of the shed will then be maximum during the flight of the shuttle so that the shuttle can pass through the shed easily without touching the warp treads.

Further, the invention is also suitable for the making of terry cloth. To this end the loom may be constructed to provide for the cloth a movement such that the cloth is moved backward only during one of a plural number of operations of the reed, e.g. on every second or third throw of the reed, the other operations of the reed being carried out with normal cloth movement. The weft threads inserted and beaten up without backward seesaw motion of the cloth are consequently not pushed so far forward by the reed as are the wefts beaten up with backward motion of the cloth. The heating up which occurs simultaneously with a controlled backward movement corresponds to the complete beating up which occurs periodically during normal terry weaving. The result is that when, in accordance with this practice of the invention, every third weft, say, is beaten up with backward motion, it carries with it the previous two more loosely beaten wefts, and the pile warp generally used in terry cloth follows this motion and forms the terry loops.

The invention will now be further described in terms of a number of non-limitative exemplary embodiments of the invention and in conjunction with the accompanying drawings in which:

FIG. 1 is a diagrammatic view in side elevation of a loom according to the invention;

FIG. 2 is a view similar to that of FIG. 1 but showing a modified form of construction and,

FIGS. 3 and 4 are respectivel diagrams showing further modified constructions according to the invention.

Referring to FIG. 1, the warp 1 passes from a warp beam 2 over a back rest 3 which is rotatably mounted at each end in one arm 4 of a two-armed lever, the other arm of which is indicated at 6. This lever is pivoted at 5. A tension spring 7 engages the arm 6 and tends to rotate the lever clock-wise as seen in FIG. 1 so that the warp is kept tight. The construction of the elements 3 to 7, shown only diagrammatically in the drawing, is such that the tension on the warp is the same for all positions occupied by the back rest 3 during operation of the loom.

From the back rest 3 the warp then passes through a warp stop motion 8 made up of a multiplicity of thin strips. It then passes through heddles 9 to'forr'rfa shed 11 and then through a reed 12 to the fell of the cloth, indicated at 13. The cloth passes through spreaders 14, over a breast-beam 15 and over a deflecting roller 16 to the cloth draw-off roller 17. It is then wound over another deflecting roller 18 and onto a cloth beam 19 which is driven by means of a slipping clutch not shown.

The reed 12 is mounted on a sley 21 supported on a sley lever 22. The lever 22 oscillates about a shaft 23 and has aflixed thereto a second lever 24, the levers 22 and 24 being fixed with respect to each other. The lever 24 carries a roller 25 cooperating with a cam 26. The reed is thus driven by the cam 26. A link 27 engages the free end of lever 24 at a slot 28 in the latter. The other end of the link 27 is coupled to a lever 32 rotating about the pivot 31 of the deflecting roller 16. The points of pivotal coupling between the ends of link 27 and levers 24 and 32 are adjustable lengthwise of slots 28 and 29 in those levers. The breast-beam 15 is pivoted on an arm 32' of lever 32, fixed with respect to the latter so that the breast-beam oscillates about pivot 31 upon oscillation of lever 32.

The loomoperates as follows: After a weft thread 33 has been inserted by means of a gripper shuttle 34, the lobe 35 of the cam 26 passes under, i.e. in contact with, the roller 25. This causes the levers 22 and 24 to rotate clockwise, driving the reed 12 to the right in FIG. 1 and beating the weft 33 uponto the fell of the cloth, which but for the mechanism of the invention would be at the position 13. The reed, however, moves all the way to position shown for it in dot-dash lines at 12a so that the front apex of the shed during beating up is defined by the reed to be at the position 13a. During the throw of the reed, however, the lever 32 and breast-beam 15 are rotated counterclockwise by action of link 27, so that the cloth moves to the left in the figure, i.e., backwards, in a direction opposite to the throw of the reed.

When the lobe 35 on the cam 26 passes out from under the roller 25 so that the reed 12 starts to move backwardly toward the left, the breast beam 15 is tilted clockwise again so that the cloth is moved forwardly to the right. By this added motion imposed on the cloth, the front apex of the shed is made to remain in fact throughout the weaving cycle substantially at the location 13a with respect to the loom, thus largely or wholly preventing its wandering backward toward the position 13, as would happen if the breast beam 15 were not pivoted backwards and forwards cyclically with the reed motion. The front apex of the shed thus remains in a position substantially fixed with respect to the flight path of the shuttle.

On the following throw of the reed, as the cam lobe 35 begins to run up the roller 25, i.e. to rotate lever 25 clockwise, the beam 15 will move back towards the left and the cycle begins again.

The horizontal distance b between the inoperative position of the reed and the position 13 to which, in the absence of the supplementary motion imposed on the cloth by the movable breast beam in accordance with the invention, the front apex of the shed would retreat after beating up, is smaller by an amount c than the distance a between the rest position of the reed and the position 13a imposed on the front apex of the shed by the reed during beating up. This distance c is known as the fell variation.

If the front apex of the shed is kept at 13a, the warp threads remain in the position indicated in the drawing at 1a. The shed is thus extended by the invention towards the right and the angle between the upper and lower halves of the shed is smaller. Likewise, at any given position to the rear of the fell, the vetrical distance between the warp threads in the upper and lower halves of the shed is greater than if the front apex of the shed were at 13.

In the embodiment of FIG. 1 the supplementary mo tion imposed on the cloth by the invention holds the cloth in its forward position during most of the working cycle and moves it rearwardly for a minor fraction thereof at 4 the time of actual beatingup.- This is evident from the fact that, by reason of the shaping of cam 26, during most of each revolution of the cam (which occur one per pick, the beam 15 is stationary in its right-hand, forward sition.

In FIG. 2 in contrast, the opposite is true. During most of each revolution of the shaft 23a of FIG. 2, the beam 15 is in its rear, left-hand position, and moves to its righthand forward position only when the roller 25 is lifted by the high part or lobe 35 of the cam. In FIG. 2 the shaft 23 of the reed is driven by means not shown, and the shaft 23a has a drive separate from that of the reed. Thus the shaft 23a may rotate at a rate of revolutions per minute smaller than the rate of cyclical ocillation of the shaft 23 which drives the reed.

In FIG. 2 the roller 25 is mounted on a lever having two arms 37 and 38 which is pivoted at 36. A link 27, adjustable at both ends and indicated at 27, drives the breast beam 15 between forward and rearward positions, the rear position of which is shown in dashed lines and the separation of which is indicated at d. This motion d of the breast beam may be greater than the fell variation 0. Because of the low speed of the shaft 23a the seesaw motion imposed on the cloth according to the invention may be applied in a pattern or program including less than one motion per working cycle of the loom.

Alternatively, the shaft 23a may 'be driven at the same revolutions per minute as the number of oscillations per minute of the shaft 23 and reed 12. By suitably adjusting the position of the cam 26 about the shaft 23a, the phasing of the breast beam motion can be adjusted, for example to achieve a forward motion of the cloth just before each pick and backward motion immediately after the pick, or during the following throw of the reed.

In the embodiment of FIG. 3, the breast beam 15 has fixed pivots. The cyclical forward and backward movement of the cloth is produced by a mechanism which adds a supplementary motion into the drive of the cloth draw-off roller 17. This roller is provided with a worm wheel 41, fixed co-axially with respect to the roller 17. The worm wheel meshes with a worm 42 keyed to a drive shaft 43, but free to permit relative longitudinal motion between the worm and shaft. The left end of the worm is engaged for such longitudinal motion by a lever 44 pivoted at 45 and driven by a reciprocating link 47 pivoted to the other end 46 of the lever.

During operation, the shaft 43 and its worm 42 are rotated 'by the main shaft of the loom, either continuously or intermittently, so as to rotate the roller 17. The cloth is thus pulled off the breast beam and supplied to the cloth beam 19. At the desired phase in each working cycle or in each of the selected number of working cycles (e.g., every third or fourth), or even according to a more complicated program, the link 47 is moved longitudinally, backwards or forwards or both. There is thus imposed a supplementary rotation on the roller 17, by sliding motion of the worm 42 on the shaft 43 through the operation of the levers 44 and 46. In this way there may be imposed on the cloth supplementary motions as described in connection with FIG. 1 and having the effect there described on the position of the front apex of the shed. The link 47 may, for example, be coupled to a card dobby built into the loom to control the heddles.

In the embodiment of FIG. 4, a differential gear 51 is included in the drive for the draw-off roller 17 so as to permit the superposition of two motions. In addition to the continuous drive of the shaft 43, the differential receives a drive from a shaft 52 and pinion 53 meshing with the toothed rim 54 on the housing 55 of the differential. The two drives at 43 and 52 are thus added together and the driven shaft 56 can thus be caused to move successively at two speeds by the imposition of a discontinuous rotation on shaft 52. This rotation is passed via bevel gears 57 and 58 to the draw-01f roller 17, gear 58 being fast to the roller 17. Thus the rate of rotation of the roller 17 can be momentarily speeded up or slowed down, and moreover the cloth can be momentarily moved or hitched forwards or backwards.

In accordance with the invention, the combination of the two motions imposed on the cloth may be arranged to drive the cloth momentarily faster, as for example immediately prior to the pick or to move momentarily backwards during the throw of the reed and to move it forward again immediately after. This can be achieved in the embodiment of FIG. 2 by employing a cam 26 having suitable lobes and can be achieved in the embodiments in FIGS. 3 and 4 with suitable drive mechanism associated with the link 47 of FIG. 3 or the shaft 52 of FIG. 4 and operated a number of times during each working cycle of the loom.

In the embodiments in FIGS. 3, 4, the distance covered 'by the cloth in each momentary forward or backward movement may be variable according to a definite program instead of being the same every time. By means of the resulting irregular weft spacing special effects can be produced in the cloth. Also, when making terry cloth, changing the momentary backward movement of the cloth during every third or fourth throw of the reed, for example, will mean that the loops 61 (FIG. 2) of pile warp 62 which form in the terry cloth will be of different heights.

In embodiments such as those of FIGS. 1 and 2, instead of a movable breast-beam there may be employed a bar-like element which is moved backwards and forwards at right angles to its axis, e.g. an angle iron or the like. The element must be arranged at a position where the cloth is diverted, i.e. changed in direction of travel, preferably a position between the beat-up position of the reed and the cloth draw-01f roller. A change in the position of the element when so sited shortens or lengthens the path of the cloth and consequently moves the cloth backwards or forwards. The tension of the cloth 10 and the warp threads 1 is always taken up by the tension beam 3, which pivots slightly upwards when the cloth moves backwards and slightly downwards when the cloth moves forwards.

It will thus be seen hat the invention provides a loom comprising a warp beam, a cloth beam, means to advance the warp threads and the cloth woven therefrom, and shedding mechanism diagrammatically illustrated in the drawings at the heddles 9. The heddles are driven in customarily fashion so as, for example, to change the shed once for each throw of the reed. Moreover, the loom includes picking mechanism which may be conventional in nature and which drives the shuttle shown at 33 in the drawings through the shed in timed relation with the operation of the shedding mechanism and of the reed so as to insert, for example, one weft thread for each shed change. The loom of the invention further includes supplementary means for altering the advance of the cloth in timed relation with the drive of the reed. In the embodiments of FIGS. 1 and 2, the supplementary means include a member-which there takes the form of the breast-beam 15 of the loom-extending transversely of the loom at a location between the reed and the cloth beam. The cloth passes over this transverse member with a change of direction in its passage from the general location of the reed to the cloth beam, and means are provided to shift this member transversely of its own length so as to impose a supplementary motion on the cloth in the direction of the warp threads, speeding up or slowing down the motion of the cloth and optionally causing a brief reversal thereof, all in a cyclical manner and in timed relation with the operation of the reed and shedding mechanism. This timed relation is specifically illustrated in the embodiment of FIG. 1 where the drive to the reed and to the breast-beam 15 are both derived from the shaft which rotates the cam 35. In the embodiment of FIG. 2 the oscillating shaft 23 which drives the reed and the shaft 2311 which drives the cam 26 for oscillatory motion of the breast-beam 15 are both linked, by mechanism not shown, to a common source of motion which may conveniently be the main shaft of the loom.

In the embodiments of FIGS. 3 and 4, the supplementary means for altering the advance of the cloth in timed relation with the reed comprises the longitudinally reciprocating link 47 in FIG. 3 and the shaft 52 in FIG. 4. While reed has not been shown in FIGS. 3 and 4, it may have in those embodiments the same construction and drive as that which is illustrated in FIG. 2 and which has been hereinabove described for FIG. 2 as including a coupling of the reed to the main loom shaft.

In the embodiment of FIG. 3, the shaft 43 may be coupled to the main shaft of the loom to rotate either continuously or intermittently, and the link 47 may also be coupled to the main loom shaft for oscillatory motion in timed relation with the drive to the reed and shedding mechanism although, as has already been stated, the cyclically motion of the link 47 may be at a frequency which is not the same as that of the cyclical operation of the reed and shedding mechanism.

In the embodiment of FIG. 4, the shaft 43 may have the same form of coupling to the main shaft of the loom as has been described for FIG. 3. The shaft 52 has a motion similarly related to the main loom shaft as was described for the link 47 of FIG. 3, except that the shaft 52 of FIG. 4 has rotation instead of reciprocating linear motion. Thus the shaft 52 may be rotated at a cyclically varying rate, either continuously or discontinuously.

While the invention has been described herein in terms of a number of preferred embodiments, the invention itself is not limited thereto; rather, the invention comprehends all modification of and departures from those embodiments properly falling within the spirit and scope of the appended claims.

I claim:

1. A loom comprising a Warp beam, a back rest, means movably supporting the back rest, resilient means engaging said support means to apply a substantially constant tension to warp threads passed over the back rest, a shedding mechanism, a reed, means to drive the reed in timed relation to the shedding mechanism, a cloth beam, a member extending transversely of the loom between the shedding mechanism and cloth beam, and a cam-operated linkage coupled between the means to drive the reed and said member to oscillate said member and thereby to superpose a controlled reciprocating motion on the normal advance of the cloth at the fell thereof.

2. A loom according to claim 1 wherein said linkage operates at a cyclical time rate lower than the operation of the reed.

3. A loom according to claim 1 wherein said member is the breast-beam of the loom.

4. A loom according to claim 1 wherein said linkage includes separate cam shafts for drive of the reed and drive of said member.

5. A loom according to claim 1 wherein said member comprises a draw-off roll, said linkage comprising a worm wheel coupled to said roll and an axially reciprocating worm engaging said worm wheel.

6. A loom according to claim 1 wherein said member comprises a draw-off roll, and wherein said linkage includes a differential gear coupled to said draw-off roll.

References Cited UNITED STATES PATENTS (Other references on following page) 7 8 STATES PATENTS FOREIGN PATENTS Blanchard 139-25 19,752 6/ 1899 Switzerland. Burdett 13 9 309 169,008 7/1934 Switzerland. IDraper Germany.

Palmer 139-304 MERVIN STEIN, Primary Examiner. Mobarg 13925 JAMES KEE CHI, Assistant Examiner. Kopplernan et a1. 13 9-304 X Pfarrwaller 139--1 10 Cl. X.R. Pfarrwaller 139-110 X 10 13-9-25, 309 

